Chapter 3.1

Question 1

Describe the role of collagen and its characteristics

Answer 1

• it makes up the extracellular matrix of connective tissue

- >it is found throughout the body and helps with strength/flexibility

Question 2

Describe the role of elastin and its characteristics

Answer 2

• another important characteristic of the ECM
• > primary role is to stretch and recoil like a spring
• > this restores the original shape of the tissue

Question 3

Describe the role of keratins and its characteristics

Answer 3

• keratins are intermediate filament proteins found in epithelial cells
• > function as regulatory proteins and contribute to the mechanical integrity of the cell

Question 4

Describe the role of actin and its characteristics

Answer 4

• it makes up microfilaments
• > and thin filaments in myofibrils
• > it is the most abundant in eukaryotic cells

Question 5

Describe the role of tubulin and its characteristics

Answer 5

• it makes up microtubules
• > provides structure
• has polarity
• > negative end is usually located next to the nucleus
• > positive end is in the periphery of the cell

Question 6

Describe the structure of myosin. Which other structural protein is it mostly involved in

Answer 6

• myosin has a single head and neck
• > movement of the neck is responsible for the power stroke
• > it acts with actin

-it is also involved with cellular transport

Question 7

What motor proteins are associated with microtubules

Answer 7

• kinesins and dyneins
• > have two heads
• kinesins bring vesicles toward the positive end of microtubules
• dyneins bring vesicles to the negative end of microtubules

Question 8

Describe the role kinesis and dyneins play in neuronal transport

Answer 8

Kinesins
->bring vesicles of a neurotransmitter to the positive end of the axonal microtubules

Dyneins

• > bring vesicles of waste or recycled neurotransmitters to the negative end of the microtubule(the soma)
• > through retrograde transport

Question 9

What are binding proteins. Give examples.

Answer 9

• proteins that bind to other proteins
• > to stabilize or transport them
• > each has an affinity curve for its molecule of interest

Examples are:
->hemoglobin, calcium-binding proteins and DNA-binding proteins

Question 10

What are cell adhesion molecules

Answer 10

• they are molecules found on the surface of most cells

- >aid in binding the cell to the extracellular matrix or other cells

Question 11

What are the three types of cell adhesion molecules

Answer 11

-adherins, integrins and selectins

Question 12

Describe what cadherins are. Note different type of cells use different type of cadherins

Answer 12

• they are a group of glycoproteins
• > mediate calcium dependent cell adhesion

-they often hold similar cell types together

Question 13

Describe what integrins are.

Answer 13

• group of proteins
• > two membrane spanning chains called alpha and beta
• > they are important in binding and communicating with the extracellular matrix
• > also play a role in cellular signalling
• > play a role in cellular function such as cell division as well

Question 14

Describe what selectins are. Their role. Note that selectins have the weakest bonds formed out of all the cell adhesion molecules.

Answer 14

• unique
• > because they bind to carbohydrate molecules that project from other cell surfaces
• selectins are expressed on white blood cells and endothelial cells that line blood vessels
• > they are involved with inflammation and white blood cell migration

Question 15

What kind of cells are antibodies produced by?

Answer 15

• they are produced by B cells

- >these cells function to neutralize targets in the body

Question 16

Describe the characteristics of antibodies. Specifically the general structure

Answer 16

• they are made up pf two identical heavy and light chains
• > disulfide linkages and noncovalent interactions hold the heavy/light chains together

antigen-binding region

• > at the tip of the “Y” for the antibody
• > specific polypeptide sequences that will bind(only one type of antigen sequence that will bind)

constant region
->involved in recruitment and binding of other cells of the immune system such as macrophages

Question 17

What are the three things that can happen when antibodies bind to their targets, the antigens?

Answer 17

1) neutralize the antigen
- >making the pathogen or toxin unable to exert itself on the body

2) Marking the antigen(pathogen/toxin) for destruction
- >this process is known as opsonization

3)Clump together(agglunation)